Valproic Acid

Seizure disorders affect the brain’s ability to transmit electrical impulses and to regulate nerve activity. During a seizure, a patient may experience changes in consciousness, alterations in sight, smell, and taste, and may experience convulsions. Seizures are associated with acute conditions, such as high fevers, head trauma, severe infections, and exposure to toxins, and with chronic conditions such as metabolic disorders and brain tumors. In many cases, the cause is not known. The frequency of seizures varies from a single episode, to occasional seizures, to recurrent. Rarely, a patient may have a seizure that does not stop without prompt medical intervention. People may experience some fatigue and a short period of confusion after a seizure. Muscle contractions during a seizure can lead to an injury and, in some cases, recurrent seizures can eventually lead to progressive brain damage, but for most people there will be little or no residual damage.

Bipolar disorder is a mental condition that is characterized by cycles of depression and mania that may last for days, weeks, months, or years. During a depressive episode those affected may feel sad, hopeless, worthless, and have thoughts of suicide. During a manic episode, those affected may be euphoric, irritable, use poor judgment, and participate in risky behaviors. Valproic acid is prescribed to help even out the moods of the person with bipolar disorder, especially mania. It is also given to some patients with recurrent migraine headaches, not so much as to treat migraines but to help prevent their occurrence.

Valproic acid levels must be maintained within a narrow therapeutic range. Too little and the patient may experience a recurrence of symptoms (seizures, mania, or migraines); too much and the patient may experience increased side effects. This balance is not always easily achieved. The drug is metabolized by the liver and is processed at a rate that varies from patient to patient and is affected by a patient’s age and the health of their liver. In addition, valproic acid levels are often affected by other drugs such as carbamazepine, phenytoin, lamotrigine, and phenobarbital. They increase the rate of valproic acid metabolism, thus decreasing its concentration in the blood.

Dosages of valproic acid must be adjusted carefully until a steady concentration in the blood is reached. The actual amount of drug that it takes to reach this steady state will vary from person to person and may change over time.